4-neopentyl-1,2-dithia-4-cyclopentene-3-thione and 4-methyl-5-tertiary-butyl-1,2-dithia-4-cyclopentene-3-thione



. hours.

complete when the pressure within; the reaction Patented Dec. 26, 1950 UNITED STAT E s rATENT OFFICE TERTLARY BUTYL 1,2 DITHIA 4 CY- CLOPENTENE-3-THIONE Donald R. Stevens, Wilkinsburg, and William C.

Starnes, Pittsburgh, Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware N Drawing. Application March 7, 1947,

Serial No. 733,196

13 Claims. (o1, 260-327) This invention relates to new chemical com- These compounds are two in number and both have the empirical formula Cal-1:283. Accordingly, they are isomeric with each other. One of the compounds is a bright orange-colored crystalline solid having a melting point of about 87 C.; the other is a redpoint of about 80 C. Both are substantially insoluble in water, but are soluble in a variety of organic solvents, including benzene, acetone, methanol, pentane, and ethyl ether.

tives in certain hydrocarbon fuel compositions.

The new chemical compounds provided by the invention are formed simultaneously by direct in dish-orange crystalline solid having a melting They are useful as chemical intermediates and as addireaction between sulfur and di-iso-butyle'ne at,

drocarbons, e. g., as it occursin the hydrocarbon mixture obtained by the cold acid polymerization of butylenes.

The reaction takes place readilyat temperatures above about 140 C. under autogenic pressure. Accordingly, it is conveniently carried out simply by charging the desired quantities, of the two reactants into an autoclave or other suitable pressure vesscLand heating to the desired reaction temperature. Ordinarily, the reaction is carried outat temperaturesbetween about 140 C. and about 200 C., but if it is desired to favor the yield of the isomzr which melts at 80 C., higher temperatures, e. g. up to about 350 C., are employed. The time required for completion of the reaction varies with the temperature employed as well as with. the purity of the reactants and the ratio in which they are employed. At a reaction temperature of about 350 C., for example, the reaction, is substantially complete in as little as minutes or less, whereas at a temperature of about 170: C., completion of the reaction may take 3-5 hours, and at lower temperatures may take as long as 1-0 Ordinarily, the reaction is considered vessel levels off at a constant value. The molar ratio of reactants maybe varied between about .1 and about 5 moles of sulfur per mole of di-isobutylene, but optimum yields of the" crystalline compounds are usually obtained when employvmelting at about 81 C.

ing about 2.5 moles f sulfur per mole of diisobutylene.

Upon completion of the reaction, the crude reaction product is obtained in the form of a dark oily liquid, usually containing a small quantity of mar eacted sulfur and having the odor of hydrogen sulfide. The desired CaHnSs compounds are readily recovered from the crude liquid reaction product by dissolving the latter in a miscible organic solvent, e. g., petroleum ether, pentane, toluene, etc, filtering off any unreacted sulfur, and thereafter cooling the resulting solution until the SOhd products precipitate out or solution as a mass of orange-colored crystals which are then filtered off and washed with small quantities of the solvent. In some instances, particularly when the crude liquid product has been allowed to stand in the reaction vessel for an extended period of time, it may be found that a small quantity of the CsrfmSs compounds has crystallized out of solution. iliese crystals may be recovered by an initial nitration oi Bile crude reaction product, and then added to the main bulk of the crystalliZc-Ci product prior to the washing step.

The crystalline product isolated from the crude reaction product as described above consists or a mixture 01 the two Cal-111253 compounds. The ratio in which the two isomers occur in such mixture depends somewhat upon the conuitions of the suhulizatlon reaction and upon the articular organic solvent em loyed in recovering the mixture from the CldQG reaction product. Ordinarily, however, tne mixture will contain about 25-4J per cent by weight of the Cal-112583 isomer which melts at about 250 C., and about 6D-75 per cent by weight or the isomer This mixed product is an orangecolored crystalline solid having a melting point between about 50 and about C., depending upon tne ratio in which its two components are present. For many purposes, the mixture may be employed in lieu of either of the pure compounds, and in certain instances it may even be preferred. For example, in employing the new compounds as additives in certain petroleum fllol compositions, as hereinafter more fully explained, the mixed compounds are but may advantageously be marketed and used as such.

When desired, the individual CsHmSa comofabout:170- C. for 3 hours.

cases slightly less soluble in organic solvents;

than the low-melting compoundand according;- ly it may be isolated by repeated crystallizations. from organic solvent solutions, The lo-melting isomer may be recovered from the combined mother liquors from such a series of crystallizations. Among the various organic solvents which I may be employed in separatingthe-isomers'by fractional crystallization, chloroform has; been found to have superior differential solvent'power for the two isomers. method for separating the isomers COIlSlStSziILdlS-i solving the mixture in chloroform and thereafter cooling the resulting solution to a low temperatureto permit the higher-melting isomer to crystallize out of solution. The crystals maybe separated from the mother liquor by filtration orjcentrifuging, and if an especially pure product isdesired, it may be subjected to a second crystallization from chloroform solution; Ordinarily, however, a'single crystallization will yield a productofsufiioient purity for most purposes. The low-melting isomer is preferably recovered from the chloroform mother liquors by evaporating offf the chloroform andpurify-ing the residue by one or more crystallizations from an organic solvent such as petroleum ether, pentane, diethyl ether; etc.

The following examples will-illustrat several ways in whichthe principle of the invention has been applied; butare not to be construed as limiting the same.

EXAMPLE I Approximately 224 parts by weight of. diisobutyiene, consisting of about 80 per cent by weight of ZAA-trimethyl-pentene-l and about 20 per cent by weightof ZAA-trimethyl-pentenee2 and approximate1y320 parts by weight of sulfur were charged into an'electrically-heated rotating autoclave and heated at a temperature During theheating the maximum pressure developed within the autoclave'was about 150 pounds per square inch. The crude reaction product obtained was-adark oilyliquid having an odor of hydrogensul-fide. It wasfiltered to remove any unreactedsulfur, andwas then diluted with an equal volume of pentane. The pentane solution-was chilled to a. temperature of about 80 C., wherebythere separatedout oi solution an orange-coloredcrystalline mass comprising the two isomeric C8H12S3 compounds. The crystalline product wasfiltered oft-and dissolvedin an equal amountcof chloro form. Upon cooling the chloroform solution .to a temperature of about 80? C., a bright orangecolored crystalline solid separated out of solution. This product was filtered off and was further purified by a second crystallizationfrom chloroformvsolution. The recrystallized product had ,a melting point of about87 C., and the following analysis:

Accordingly, a. prefer ed:-

Thechloroform mother liquors obtained above were combined. and heated to evaporate the chlorofprm, wher eby there was obtained a darkcolored oily viscous liquid. This material was diluted with equal volumes of pentane and diethyl ether and was cooled to a temperature of about- ;-8,) C., whereby an orange-colored crystalline product separated out of solution. This productwasfilteredofi and was purified by several recrystallizations froma mixture of pentane and diethylfether. When dried, the recrystallized product, was appreciably difierent in color from the orange-colored crystalline product previously, isolatcd,.being darker. and having a distinct reddish cast. It had a. melting point of about 80? C., and the following analysis:

Further analytical data and chemical characteristics indicate that this product is probably j methyl- 5 tertbutyl- 1,2- dithia 4- cyclopentene-3-xthione.

EXAMPLE 11;

Approximately 84 parts. by weight of (iii-i50- butylene, consisting of abOut 80' per cent bylweight 0i" 2,4,4-trimethyl-p entenee1 and about; 203 per centby weight" of 2AAetrimethylepentene-l and about 96 parts by weight of sulfur were heated together in aclosed vessel at a temperature of 150.16 0f"C. for about 10 hour'sl During the heating, the maximum pressure developed .within ,the vessel was-about pounds per square inch. At the end of'the heating period, the vessel was al- IQWGQIOHCOQI, after, whichjit was opened and the contentswere withdrawn, The crude reaction product soobtainedwas a visc0u's dark red oil having th'e odor of. hydrogenjsulfide and containing asmall amount .of 'a,crystal1ine solid material. The entire productfwas. dissolved in an equal volume oj ethyl ether and wassfiltered to ,remove any unreacted sulfur. The filtered'solutionwas hen low t sta d t i if rfinours. whereby an orange-gcolored solid'crystallized out of solution. This '=product Was fiItered off and was recrystallized several times from hot ethyl falcohol solution to obtain a pure product having a melting point;at'86;5-=8'7:3 C; Carbon, hydrogen, sulfur; and molecular weightdeterminations showed this product to have the" empirical formula C8H12S3; The ethyl alcohol motherliquors were not processed in this instance --for recoveryof the lower-Inelting isomer Approximately- 336 parts by weightiof butylene dimer; obtained by the cold acid polymerization of mixedbutenes; and =288*parts by weight-ofsu1- Specific gravity, 60/60 F 0.716 Boiling range, F 187-234 Bromine number 140.9

During the heating period, the maximum pressure developed within the autoclave was about 75 pounds per square inch. Upon completion of the heating, the autoclave was cooled and there was withdrawn approximately 608 parts by weight of a crude reaction product. This product was filtered, whereby there was obtainedapproximately 137 parts by weight of a solid product. This product was dissolved in diethyl ether and filtered to remove free sulfur. The filtered solution was then heated to evaporate the ether, whereby there was obtained approximately 85 parts by weight of an orange-colored solid. This product Was purified by several recrystallizations from diethyl ether solution, whereby there was obtained a crystalline material having a melting point of 865 0., and which was found to be identical with the Cal-11283 compound prepared as described in Example II. An additional quantity of this compound as well as a quantity of theisomer of 80 C. melting point may be recovered from the liquid portion of the initial reaction product by treatment as described in Examm As hereinbefore stated, both of the Cal-1 .233 compounds, as Well as mixtures thereof, are useful as additive agents in certain hydrocarbon fuel compositions. It has been found that these products when added in small amounts to petroleum oil fractions of the Diesel fuel range have the property of decreasing the ignition delay period of such fuels as indicated by an increase in the cetane number of the fuel. Ordinarily, the CaHmSs compounds, or mixtures thereof, are added to the fuel in an amount, representing between about 1 and about 5 per cent by weight of the entire composition, although in fuels for heavyduty continuously-operating Diesel engines the proportion of additive may be increased to as much as per cent by weight. In such case it is preferable to employ a mixture of t-e two compounds, conveniently the mixture initially isolated from the crude liquid reaction product,

since such mixtures are more soluble in hydrocarbon fuel oils than either of the separate compounds, and henc have less tendency to separate out of solution during shipping and storage of the fuel composition. The following solubility data illustrate this property:

The following table presents data illustrating the use of one of the new compounds and a mixture thereof with the other as cetane number improvement agents in a typical Diesel fuel composition. These data were obtained by determining the cetane number, as described in SAE 6 Journal, June, 1936, page 225, of the compositions set forth in the table.

Table Compo- Composition Composi-' sition I II tion III Fuel Base, per cent by wt. 97. 88 95. 76 Additive Employed None CaHnSs Mixed P. 87 C CiHuSs Coinpounds Additive, per cent by wt 2.12 4. 24 Gravity, API 31. 7 31. 0 31. 1 Pour Point, "F 35 20 -25 Viscosity at 100 F., SUV... 38. 5 38. 6 39.0 Cetane Number 45. 5 50. 4 r 55.3

Increase in Octane No. over Base Fuel 0 4. 9 9. 8

1 Mixture comprised approximately 60 per cent by weight of high- .melting isomer and approximately 40 per cent by weight of lowmclting isomer.

Other modes of applying the principle of our invention may be employed instead of those explained, change being made as regards the materials or methods employed provided the product stated by any of the following claims be obtained or the step orsteps stated by any of the follow- -1,2-dithia-4-cyclopentene-3-thione.

3. As a new chemical compound, 4-methyl-5- tert-butyl-1,2-dithia-4-cyclopentene-3-thione.

4. An orange-colored crystalline solid product consisting of a mixture of the two isomeric crystalline solid compounds 4-neopentyl-l.,2-dithia- 4-cyclopentene-3-thione and 4-methyl-5-tert-butyl-1,2-dithia-4-cyc1opentene-3-thione.

, 5. The process which comprises heating a mixture of sulfur and di-isobutylene at areaction :temperature above about C. and under autogemc pressure, dissolvin the reaction product so obtained in an organic solvent, cooling the resulting solution to cause precipitation -of 'an orange-colored crystalline product having a melting point between about 50 C. and about 70 C. and consisting predominantly of a mixture of 4 neopentyl 1,2 dithia-4-cyclopentene-3-thione and 4-methyl-E-tert-butyl-1,2-oithia-4-cyclopentene-3-thione, and separating said crystalline product from the mother liquor,

6. The process which comprises heating a mixture of sulfur and di-isobutylene at a temperature between about 140 C; and about 350 C- and under autogenic pressure, dissolvin the reaction product so obtained in an organic solvent, cooling the resulting solution to cause precipitation of an orange-colored crystalline product having a melting point between about 50 C. and about 70 C. and consistin predominantly of a mixture of 4 neopentyl-1,2-dithia-4-cyclopentene-3-thione and 4-methyl-5-tert-butyl-1,2-dithia-4-cyclopentene-3-thione, and separating said crystalline product from the mother liquor.

7. The process which comprises heating a mixture of sulfur and di-isobutylene at a temperature between about 140 C. and about 350 C. and under autogenic pressure for from about 10 minutes to about 10 hours, between about 1 and about 5 moles of sulfur being employed per mole of diisobut-ylene, dissolving the, reaction product, so obtained in an organic solvent, coolingthe resulting solution to cause precipitation of an orange-colored crystalline product having a meltr ing-point between about 50 C. and about 70 C. and consisting predominantly of a mixture of 4-- neopentyl 1,2 dithia-4-cyclopentene-3-thi one and 4-methyl-5-tert butyl-1,2-dithia-4-cyc lopentener3-thione, and separating said crystalline product from the mother liquor.

8.7 The process which comprises heating a mixture of sulfur and di-isobutylenein a molecular ratio of about 2.5 moles of sulfur per mole of diisobutylene at a temperature betneen about 140 C. and about 200 C, and under autogenic pressure for from about 3 to about Shours, dissolving the reaction product so obtained in an organicsolvent, cooling the resultin solution to cause precipitation of an orange-colored crystalline product having a melting point between about 50 C, and about 70? Q, andconsistingpredominan y f a m re f neone ty le dithiariy i pent -thi9nc and ethy -5- tertrbu y 1,2 di iv c l en en -thhne, and. separ tin sa d c al ine pr duc f m the mother liquo 9- he pr which om r ses-heatin .t l-tinieture of su fur and b it lenea a temperature between about 140 Q, and about350 C, and under autogenic pressure, dissolving the crude reaction product so obtained an organic solvent and co ling th r su ing sol tiqh te e ecipitation o a stalliheproduct con s n p edominantly o a m xt re, o i-ri tentylshz- QiBDZ kbGY OPB ltEI Q-3W192 and i-mc hyi t u y di hi e -oyolo en e- 3- hih separatin a d p uc fr m t mo her iq d dissolving it, i h rofo m mq ng the resulting lu o to us precip ati oi- -n pentyl-1 2 Qi h a i cycli 'pfllitfiilfi- -tK Q -Q tenasaid e-heopc t l-l g th a- -w cloptm teneefir hipnefr m th mo h r L qu and; ecovering irorn said mpther liquor the lv-rnethyl- -trt-b1ityl;- 2-dithi yfi ti ten fiqh 9, The pr cess which mp is heat gam itture of and di=i cbutyi e ie am lar r ti otbetweenahout nd bo 5 moles o Sulfu pen mole oi d i-is bu lenei at a mperature between about 14.9? and a ut 359 ra unde auto enic ressure fo m a out; 1. minute to abou 1. hour d sso ng he rude r a tip product so o ta ed n or ni sq velitti coolin he resultin oliiti l to 3. 156 EPW32 tation of a crys lline odu onsistin redominantly o a m xt re o -neonentrl-L2- dithial-cyclopentene-B-thione and L-methyL- E- tertebutyl 1,2 dithiar4wyclopentene-3-thione, separating said product from the mother liquor andwdissolving it in chloroform, cooling the. re-

suit n seiutiee o cause ntee eitetitn i ihat: heonen y r-iizv i i f re qi he eparating, sa d orie it i I i ii hte e-art iohe. f reco erin -fro o -i i.-Laetitia= o izsiiiieee+ 11. The process which coinprises heat;nganiix tu r-e oi sulfur-and di-isobutylene in. a molar. ratio cfgbetween about 1 and about 5- moles ofqsulfur per-mole of di-isobutylene at a temperatunebetwee aboiit W 9-. nd eboiittiif and limit? utqeenic p essure it! ir m abo t lqm eli w cyclope tenehi he and i'eh th fi tui i-1 2- iiih a= -cyQ1o entspe-it= hi9ne s tin sai produc rom the. mtthe f iquorf i' c eili ine it. ato a 9. 19? rom oluti i 1h h oroform ti? obt ihthe,i ieop h h fir ithieir y clopfiil fin firthiQne eatin th qhlo qi i mat iciioiist e a orate h thi m cr ii' th rerom n r cr stal zin the eSidh at =i tQ fr m sol tion i an. o nic Q v i o. we h v e-meth -5-t t:but 1= 2di hi i 9pntenev-fioh l;- Th m h d of e aratin -neon ntyk ii hiai' i pe tene-3- hit h. item. a t re th reof ith -meth 1i--te .-but yclohenteli tr hi iie wh ch toi ihr i f it his. sa imi tflli in hlc oiorm ebciii th resulting solution to cause precipitation of sai l Qpt :1 2?d i litt txql ptlltfinfi 3, ji

se ratin sa d ir iQ hthti lfiriiithiricys cn nteriehione irqmthe mother li it 1.3. Themethod oi separ tin r s op ityfi Qiiilitt f 9PIlP I 2h? and -ii eth 5'1- r -tut r -d thia-i-t cl hen eii 1 3. t mr t mirth; e then hith, com ris ci stiiisaid mixtu e, in. iiiomioi'mi oolin the, esii is tni ition s a e ci itat n t the necpent -dithiar QYQl P-WAWH, 3 h i sei erat h d c iiiptiinqirsim the mot er' i'a ior. an rom said mother isi i t e meth rMeat:bui ialertiith aei xclcmnt' negr-W929 r a o DONALD smiths; WILLIAM c,

REFERENCES (312mm UNITEP SIATE PATEMIfi 

1. A SULFUR-CONTAINING CHEMICAL PRODUCT SELECTED FROM THE GROUP CONSISTING OF (1)4-NEOPENTYL-1,2-DITHIA-4-CYCLOPENTENE-3-THIONE, (2) 4METHYL-5-TERT-BUTYL-1,2-DITHIA-4-CYCLOPENTENE-3THIONE, AND (3) A MIXTURE OF (1) AND (2). 